Without limiting the scope of the invention, its background is described in connection with polymeric biocides.
In response to the wide spreading of infectious pathogens (1), antimicrobial polymers, polymers that can effectively inactivate microorganisms upon contact, have attracted considerable interests (2-12). The simplest and most cost-effective method in the preparation of antimicrobial polymeric materials is to directly add antimicrobial additives into polymer structures during processing and has been extensively used in the production of woods, papers, plastics, textiles, coatings, etc. (13-14). Traditionally, the main purpose to add biocides into polymers is to protect the polymeric materials from deterioration and discoloration caused by microbial attacks (15-16). Therefore, some of the antimicrobial additives are actually preservatives, which have low antimicrobial activities and although antimicrobial are very toxic.
Recently, the development of antimicrobial additives that protect both the polymers and the users has become an urgent issue; however, successful examples are still limited (13-16). The major challenge is that to be successful, candidates of antimicrobial additives should meet the following requirements: they should be effective against a broad spectrum of microorganisms at low concentrations; they should have low toxicity to human, animals and the environment; they should be easily and inexpensively synthesized and processed; they should be compatible with the polymer, processing aids and other additives; they should have no negative impact on the properties and appearance of the polymers; they should be stable upon storage; and they should have long-lasting efficacy; etc. (14).
One example of a polymeric biocide is described in United States Patent Application 20030216581, filed by Sun, et al., N-halamine vinyl compounds and their polymeric biocides are described. More particularly, heterocyclic vinylic compounds are described that may be used to form biocidal polymers. The polymers may be used alone or grafted onto textiles, fabrics and polymers. The polymers are readily converted to N-halamine structures on exposure to a halogen source such as commercially available chlorine bleach. The N-halamine derivatives exhibit potent antibacterial properties against microorganisms and these properties are durable and regenerable.
U.S. Pat. No. 6,762,225, issued to Malik, et al., for light stabilizer composition and teaches a light stabilizer composition obtainable by mixing a polymer with at least one polyalkylpiperidine and at least one free radical generator and melt-blending of that mixture at a temperature above the melting point of the polymer and above the decomposition temperature of the free radical generator and at shear conditions sufficient to blend the components. The light stabilizers of this patent provide a method for enhancing the light stability of polymers, preferably polyolefins.
U.S. Pat. No. 6,670,412, issued to Erderly, et al., for a method of melt processing amine containing polyethylenes and teaches a processed linear polyethylenes containing an amine additive shown to exhibit improved processability through the addition of certain surfactants. The amine compounds are generally one or more hindered amine light stabilizers, amine antistats, amine antioxidants or amine based UV inhibitors. Among the melt processing parameters improved are reduced head pressure, reduced torque, reduced motor load, reduced or eliminated melt fracture, or combinations of these parameters.
U.S. Pat. No. 6,878,761, issued to Gugumus, for synergistic combinations of UV absorbers for pigmented polyolefins and teaches a polyolefin composition which includes an organic pigment, a sterically hindered amine light stabilizer and as UV absorber a mixture of a 2-hydroxyphenyl benzotriazole and a 2-hydroxyphenyl-s-triazine.